QR codes are a technology that desperately wants our attention. They appear everywhere from supermarket shelves and magazines to hiking trails and tombstones. Never heard of a QR code? You're looking at one right now. Scan the image at the top of this article, and it'll open a link to the mobile version...of this article. Very meta.

That's a pretty typical example of a QR code—occasionally useful, but often pointless. Either way, these plucky information sources are routinely ignored, and usually reviled. Here's where the next big thing in scannable coding went so horribly wrong.

QR (Quick Response) code is the trademark name for the two dimensional barcode system. It was originally invented in 1994 by Denso Wave, a Toyota subsidiary, as a way to track vehicles as they were assembled, and to scan components at high speeds. While Denso Wave does hold the patent on the technology, it has granted free licence on it, going so far as to publish the spec online, and allowing anyone to use it.

The conventional one dimensional barcodes used on virtually every consumer product are mechanically scanned. That is, they're read by physically bouncing a narrow beam of light onto the code, which can be interpreted using the pattern of light reflected off the white gaps between the lines.

QR codes, on the other hand, can not only hold 100 times more data than 1D barcodes—they can also be digitally scanned. The block of smaller black and white squares is read by a smart phone's image sensor, then interpreted by the system processor. The three large squares act as alignment targets, while the smaller square in the remaining corner acts to normalize the size and angle of the shot. As you can see from the image on the left, the blue strips near the alignment squares contain formatting information, and the remaining yellow area is the actual data that's converted into binary code and checked for errors before being displayed. The encoded data can be interpreted as one of four primary modes—numeric, alphanumeric, byte/binary, and Kanji. Other forms of data can also be displayed with the appropriate extensions.

As QR code technology evolved, it began to contain more and more information. The initial version was 21 x 21 pixels and held just 4 characters worth of data. The most recent version is 177 pixels square, and it holds 1852 characters—enough for a few pages of information. You can see a brief overview of their growth in complexity in the gallery below.

QR codes have long since expanded their usefulness beyond the automotive industry. They're used today in everything from inventory tracking, to shipping and logistics, to online ticketing (Fandango is a big fan). Bands put them on fliers to link to their videos on YouTube or set reminders for upcoming shows. Businesses use it to put Google Maps directions on a business card, automatically load a web page, or send a text/email to the company helpline. One enterprising wildlife refuge in Sanibel, Florida has installed the codes on signs along hiking trails and programmed them with information about the local fauna.

So with all these new and interesting ways to use this burgeoning technology—which, coincidentally, got a boost recently, when it was announced that the iPhone 5 would not include the competing NFC system—why aren't they more popular? According to Comscore, as of December 2011, only 20 percent of Americans, 16 percent of Canadians, and 12 percent of Spanish and UK smartphone owners actually use QR codes at all.

In part, it's because advertisers have attached themselves to QR like it's a golden teat. The rate of QR codes in magazine ads rose by five percent last year—from 3.6 to 8.4 percent, according to marketing firm Nellymoser. You can find QR codes in stores, billboards, subway ads, posters, and magazines. "It's an effort to convey the appearance of being tech savvy," Thaddeus Kromelis, a strategist at WPP's (WPPGY) Blue State Digital, told Business Insider. Unfortunately, most consumers aren't buying it.

"Advertisers are looking at every way possible that they can connect with consumers," said Forrester Research analyst Patti Freeman Evans. "Consumers aren't saying, ‘Oh, I really want to be able to connect with companies and brands.'" As such, the primary use of QR codes last year was actually for product scanning—either to recieve further information on a product or a coupon/reward—and was primarily done at home.

This is due largely to the inherent limitations that QR suffers from. The system needs a steady hand to take the shot, the proper QR app to interpret it, and a data connection to load the webpage and content. So when advertisers put QR codes on freeway billboards, or on subway ads where there is little cell reception, and expect users to then go through the trouble of installing an app just to be taken to the desktop version of the corporate website, it's little wonder why nobody bothers with it.

Thick-headed advertisers aren't the only drawbacks to QR codes, though. The codes can also be used to transmit malicious code, in what's known as "attagging." Since anyone can create the codes, it's easy to write a bit of malware, put it in a QR code, and slap that code over a legitimate tag. Some sap scans the bad code and, if his permissions are set too loosely, the code could give itself access to everything from the camera to the contacts to the GPS data. Or it could connect to an infection site loaded with browser exploits. The phone an become part of a bot net, or be used to send unauthorized texts—hackers in Russia once used QR to commandeer phones to send $6 international SMS messages.

And of course there's the open source issue—great for developers, but not so terrific for the end users just trying to read the things. There are multitudes of QR readers in every app store, and all of them offer a slightly different user experience. None of the big three (iOS, Android, or WP7) offer a native app. Plus, there is no dominant brand of reader. So users are stuck picking QR readers essentially at random, hoping for the best.

All that hassle to (hopefully) look at a company's website or (possibly) have your security compromised? It's a combination of factors that doesn't do much to spur confidence in the technology—or enhance its adoption rate.